<?php if (!defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package        CodeIgniter
 * @author        ExpressionEngine Dev Team
 * @copyright    Copyright (c) 2008 - 2011, EllisLab, Inc.
 * @license        http://codeigniter.com/user_guide/license.html
 * @link        http://codeigniter.com
 * @since        Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * Common Functions
 *
 * Loads the base classes and executes the request.
 *
 * @package        CodeIgniter
 * @subpackage    codeigniter
 * @category    Common Functions
 * @author        ExpressionEngine Dev Team
 * @link        http://codeigniter.com/user_guide/
 */

// ------------------------------------------------------------------------

/**
 * Determines if the current version of PHP is greater then the supplied value
 *
 * Since there are a few places where we conditionally test for PHP > 5
 * we'll set a static variable.
 *
 * @access    public
 * @param    string
 * @return    bool    TRUE if the current version is $version or higher
 */
function is_php($version = '5.0.0')
{
    static $_is_php;
    $version = (string)$version;

    if (!isset($_is_php[$version])) {
        $_is_php[$version] = (version_compare(PHP_VERSION, $version) < 0) ? FALSE : TRUE;
    }

    return $_is_php[$version];
}

// ------------------------------------------------------------------------

/**
 * Tests for file writability
 *
 * is_writable() returns TRUE on Windows servers when you really can't write to
 * the file, based on the read-only attribute.  is_writable() is also unreliable
 * on Unix servers if safe_mode is on.
 *
 * @access    private
 * @return    void
 */
function is_really_writable($file)
{
    // If we're on a Unix server with safe_mode off we call is_writable
    if (DIRECTORY_SEPARATOR == '/' AND @ini_get("safe_mode") == FALSE) {
        return is_writable($file);
    }

    // For windows servers and safe_mode "on" installations we'll actually
    // write a file then read it.  Bah...
    if (is_dir($file)) {
        $file = rtrim($file, '/') . '/' . md5(mt_rand(1, 100) . mt_rand(1, 100));

        if (($fp = @fopen($file, FOPEN_WRITE_CREATE)) === FALSE) {
            return FALSE;
        }

        fclose($fp);
        @chmod($file, DIR_WRITE_MODE);
        @unlink($file);
        return TRUE;
    } elseif (!is_file($file) OR ($fp = @fopen($file, FOPEN_WRITE_CREATE)) === FALSE) {
        return FALSE;
    }

    fclose($fp);
    return TRUE;
}

// ------------------------------------------------------------------------

/**
 * Class registry
 *
 * This function acts as a singleton.  If the requested class does not
 * exist it is instantiated and set to a static variable.  If it has
 * previously been instantiated the variable is returned.
 *
 * @access    public
 * @param    string    the class name being requested
 * @param    string    the directory where the class should be found
 * @param    string    the class name prefix
 * @return    object
 */
function &load_class($class, $directory = 'libraries', $prefix = 'CI_')
{
    static $_classes = array();

    // Does the class exist?  If so, we're done...
    if (isset($_classes[$class])) {
        return $_classes[$class];
    }

    $name = FALSE;

    // Look for the class first in the native system/libraries folder
    // thenin the local application/libraries folder
    foreach (array(BASEPATH, APPPATH) as $path) {
        if (file_exists($path . $directory . '/' . $class . EXT)) {
            $name = $prefix . $class;

            if (class_exists($name) === FALSE) {
                require($path . $directory . '/' . $class . EXT);
            }

            break;
        }
    }

    // Is the request a class extension?  If so we load it too
    if (file_exists(APPPATH . $directory . '/' . config_item('subclass_prefix') . $class . EXT)) {
        $name = config_item('subclass_prefix') . $class;

        if (class_exists($name) === FALSE) {
            require(APPPATH . $directory . '/' . config_item('subclass_prefix') . $class . EXT);
        }
    }

    // Did we find the class?
    if ($name === FALSE) {
        // Note: We use exit() rather then show_error() in order to avoid a
        // self-referencing loop with the Excptions class
        exit('Unable to locate the specified class: ' . $class . EXT);
    }

    // Keep track of what we just loaded
    is_loaded($class);

    $_classes[$class] = new $name();
    return $_classes[$class];
}

// --------------------------------------------------------------------

/**
 * Keeps track of which libraries have been loaded.  This function is
 * called by the load_class() function above
 *
 * @access    public
 * @return    array
 */
function is_loaded($class = '')
{
    static $_is_loaded = array();

    if ($class != '') {
        $_is_loaded[strtolower($class)] = $class;
    }

    return $_is_loaded;
}

// ------------------------------------------------------------------------

/**
 * Loads the main config.php file
 *
 * This function lets us grab the config file even if the Config class
 * hasn't been instantiated yet
 *
 * @access    private
 * @return    array
 */
function &get_config($replace = array())
{
    static $_config;

    if (isset($_config)) {
        return $_config[0];
    }

    // Is the config file in the environment folder?
    if (!defined('ENVIRONMENT') OR !file_exists($file_path = APPPATH . 'config/' . ENVIRONMENT . '/config' . EXT)) {
        $file_path = APPPATH . 'config/config' . EXT;
    }

    // Fetch the config file
    if (!file_exists($file_path)) {
        exit('The configuration file does not exist.');
    }

    require($file_path);

    // Does the $config array exist in the file?
    if (!isset($config) OR !is_array($config)) {
        exit('Your config file does not appear to be formatted correctly.');
    }

    // Are any values being dynamically replaced?
    if (count($replace) > 0) {
        foreach ($replace as $key => $val) {
            if (isset($config[$key])) {
                $config[$key] = $val;
            }
        }
    }

    $returnValue = $_config[0] =& $config;
    return $returnValue;
}

// ------------------------------------------------------------------------

/**
 * Returns the specified config item
 *
 * @access    public
 * @return    mixed
 */
function config_item($item)
{
    static $_config_item = array();

    if (!isset($_config_item[$item])) {
        $config =& get_config();

        if (!isset($config[$item])) {
            return FALSE;
        }
        $_config_item[$item] = $config[$item];
    }

    return $_config_item[$item];
}

// ------------------------------------------------------------------------

/**
 * Error Handler
 *
 * This function lets us invoke the exception class and
 * display errors using the standard error template located
 * in application/errors/errors.php
 * This function will send the error page directly to the
 * browser and exit.
 *
 * @access    public
 * @return    void
 */
function show_error($message, $status_code = 500, $heading = 'An Error Was Encountered')
{
    $_error =& load_class('Exceptions', 'core');
    echo $_error->show_error($heading, $message, 'error_general', $status_code);
    exit;
}

// ------------------------------------------------------------------------

/**
 * 404 Page Handler
 *
 * This function is similar to the show_error() function above
 * However, instead of the standard error template it displays
 * 404 errors.
 *
 * @access    public
 * @return    void
 */
function show_404($page = '', $log_error = TRUE)
{
    $_error =& load_class('Exceptions', 'core');
    $_error->show_404($page, $log_error);
    exit;
}

// ------------------------------------------------------------------------

/**
 * Error Logging Interface
 *
 * We use this as a simple mechanism to access the logging
 * class and send messages to be logged.
 *
 * @access    public
 * @return    void
 */
function log_message($level = 'error', $message, $php_error = FALSE)
{
    static $_log;

    if (config_item('log_threshold') == 0) {
        return;
    }

    $_log =& load_class('Log');
    $_log->write_log($level, $message, $php_error);
}

// ------------------------------------------------------------------------

/**
 * Set HTTP Status Header
 *
 * @access    public
 * @param    int        the status code
 * @param    string
 * @return    void
 */
function set_status_header($code = 200, $text = '')
{
    $stati = array(
        200 => 'OK',
        201 => 'Created',
        202 => 'Accepted',
        203 => 'Non-Authoritative Information',
        204 => 'No Content',
        205 => 'Reset Content',
        206 => 'Partial Content',

        300 => 'Multiple Choices',
        301 => 'Moved Permanently',
        302 => 'Found',
        304 => 'Not Modified',
        305 => 'Use Proxy',
        307 => 'Temporary Redirect',

        400 => 'Bad Request',
        401 => 'Unauthorized',
        403 => 'Forbidden',
        404 => 'Not Found',
        405 => 'Method Not Allowed',
        406 => 'Not Acceptable',
        407 => 'Proxy Authentication Required',
        408 => 'Request Timeout',
        409 => 'Conflict',
        410 => 'Gone',
        411 => 'Length Required',
        412 => 'Precondition Failed',
        413 => 'Request Entity Too Large',
        414 => 'Request-URI Too Long',
        415 => 'Unsupported Media Type',
        416 => 'Requested Range Not Satisfiable',
        417 => 'Expectation Failed',

        500 => 'Internal Server Error',
        501 => 'Not Implemented',
        502 => 'Bad Gateway',
        503 => 'Service Unavailable',
        504 => 'Gateway Timeout',
        505 => 'HTTP Version Not Supported'
    );

    if ($code == '' OR !is_numeric($code)) {
        show_error('Status codes must be numeric', 500);
    }

    if (isset($stati[$code]) AND $text == '') {
        $text = $stati[$code];
    }

    if ($text == '') {
        show_error('No status text available.  Please check your status code number or supply your own message text.', 500);
    }

    $server_protocol = (isset($_SERVER['SERVER_PROTOCOL'])) ? $_SERVER['SERVER_PROTOCOL'] : FALSE;

    if (substr(php_sapi_name(), 0, 3) == 'cgi') {
        header("Status: {$code} {$text}", TRUE);
    } elseif ($server_protocol == 'HTTP/1.1' OR $server_protocol == 'HTTP/1.0') {
        header($server_protocol . " {$code} {$text}", TRUE, $code);
    } else {
        header("HTTP/1.1 {$code} {$text}", TRUE, $code);
    }
}

// --------------------------------------------------------------------

/**
 * Exception Handler
 *
 * This is the custom exception handler that is declaired at the top
 * of Codeigniter.php.  The main reason we use this is to permit
 * PHP errors to be logged in our own log files since the user may
 * not have access to server logs. Since this function
 * effectively intercepts PHP errors, however, we also need
 * to display errors based on the current error_reporting level.
 * We do that with the use of a PHP error template.
 *
 * @access    private
 * @return    void
 */
function _exception_handler($severity, $message, $filepath, $line)
{
    // We don't bother with "strict" notices since they tend to fill up
    // the log file with excess information that isn't normally very helpful.
    // For example, if you are running PHP 5 and you use version 4 style
    // class functions (without prefixes like "public", "private", etc.)
    // you'll get notices telling you that these have been deprecated.
    if ($severity == E_STRICT) {
        return;
    }

    $_error =& load_class('Exceptions', 'core');

    // Should we display the error? We'll get the current error_reporting
    // level and add its bits with the severity bits to find out.
    if (($severity & error_reporting()) == $severity) {
        $_error->show_php_error($severity, $message, $filepath, $line);
    }

    // Should we log the error?  No?  We're done...
    if (config_item('log_threshold') == 0) {
        return;
    }

    $_error->log_exception($severity, $message, $filepath, $line);
}

// --------------------------------------------------------------------

/**
 * Remove Invisible Characters
 *
 * This prevents sandwiching null characters
 * between ascii characters, like Java\0script.
 *
 * @access    public
 * @param    string
 * @return    string
 */
function remove_invisible_characters($str, $url_encoded = TRUE)
{
    $non_displayables = array();

    // every control character except newline (dec 10)
    // carriage return (dec 13), and horizontal tab (dec 09)

    if ($url_encoded) {
        $non_displayables[] = '/%0[0-8bcef]/';    // url encoded 00-08, 11, 12, 14, 15
        $non_displayables[] = '/%1[0-9a-f]/';    // url encoded 16-31
    }

    $non_displayables[] = '/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]+/S';    // 00-08, 11, 12, 14-31, 127

    do {
        $str = preg_replace($non_displayables, '', $str, -1, $count);
    } while ($count);

    return $str;
}


/* End of file Common.php */
/* Location: ./system/core/Common.php */